Apparatus for treatment of napped fabric



Dec. 1965 w. N- SHEPPARD APPARATUS FOR TREATMENT OF NAPPED FABRIC Filed Dec. 1, 1961 INVENTOR. WILLIAM N. SHEPPARD JW-TYLTMIEF ATTORNEY United States Patent 3,222,895 APPARATUS FOR TREATIVENT 0F NAPPED FABRIC William N. Sheppard, Pensacola, Fla, assignor, by mesne assignments, to Monsanto Company, a corporation of Delaware Filed Dec. 1, 1961, Ser. No. 156,447 (Ilaims. (Cl. 68-5) This invention relates to the treatment of napped fabric. More particularly, it relates to apparatus for the treatment of a blanket fabric composed at least in part of acrylic fibers with aliphatic cyclic carbonates.

Because of their performance characteristics, acrylic fibers have found wide acceptance in blankets and the like made therefrom. In the manufacture thereof, blanket fabric normally is subjected to a napping procedure in order to increase both the aesthetic appeal and the thermal insulation properties of the blanket, as well as to conceal the weave or design thereof. Napping normally involves scratching or pricking the surface of woven blanket cloth so that some of the fibers therein are raised from the body of yarns. Napped cloth composed of acrylic fibers, unfortunately, has a tendency to shed and to form small fuzzy balls called pills.

Various physical and chemical procedures have been recommended to reduce the pilling of blankets made of acrylic fibers. In one chemical treatment, cross-bonding of the fibers in the nap at points of fiber intersections by means of a bonding agent or adhesive has been suggested. A similar effect is obtained when the fibers are bonded by partially dissolving or softening them with a solvent and then evaporating the solvent. However, while pilling is notably reduced by the prior methods, the blanket unfortunately loses its soft and luxurious touch, thereby causing the thus-treated blanket to have a harsh hand and to have an undesired stifiness.

It has been found that pilling of blanket fabric made of acrylic fibers can be reduced significantly by applying an aqueous solution of an aliphatic cyclic carbonate to the nap of the fabric and thereafter evaporating the solution to bond the treated fibers in the nap at points of fiber intersections. In addition to containing a carbonate of the aforesaid type, the solution may also contain a softening agent, an anti-static agent, water re pellent, or like additive to impart specific properties to the fabric.

It is an object of the present invention to provide an apparatus for the continuous treatment of a running blanket fabric composed of acrylic fibers with an aliphatic cyclic carbonate.

Other objects will become apparent from the following detailed description of the invention.

In general, these objects are accomplished by applying a solution of an aliphatic cyclic carbonate of a particular class to a blanket fabric composed at least in part of acrylic fibers and removing the solution therefrom in a particular manner. The application of the carbonate is made subsequent to the napping of the fabric during the manufacture thereof. The carbonate is selected from the group of cyclic carbonates including 1,2-, 2,3-, and 1,3-dihydric aliphatic alcohols having no more than four carbon atoms in their alkylene radical. Such aliphatic cyclic carbonates include ethylene carbonate, propylene carbonate, trimethylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, 2,3-butylene carbonate and isobutylene carbonate. Especially useful of the above group is ethylene carbonate. The napped fabric is continuously fed, preferably under tension, through an aliphatic cyclic carbonate application zone containing a mist, fog, or the like of aliphatic cyclic carbonate solution in finely divided form. In the zone a stream of finely divided carbonate solution preferably is suspended in a propelling gas. A predetermined amount of the finely divided solution is impinged onto one or both sides of the nap of the blanket fabric. After the solution has remained on the fabric for a time sulficient to permit partial dissolving or softening of the nap fibers, the fabric is continuously fed through a heating zone. In this zone the fabric is heated to evaporate the solution from the fabric so that cross-bonding of the nap fibers at points of fiber intersections is effected. Thereafter, the fabric is fed through a cooling zone wherein the fabric is cooled to a temperature below 150 F. before the fabric is subjected to laterally applied pressure. The thus-treated fabric is rendered more resistant to pilling without substantial sacrifice of softness of hand.

According to the preferred practice of the invention, a napped fabric comprising at least 10 percent acrylic fibers is made in a conventional manner. The fabric can be made by weaving, knitting, felting, braiding, tufting, as well as other ways. Prior to treatment with ethylene carbonate the fabric is subjected to a napping operation to produce a fuzzy, fibrous surface thereon. Napping can be accomplished in a known manner by scratching or pricking the surface of the fabric so that some of the fibers are raised from the body of threads composing the fabric. While the fabric may be narrow, ordinary blanket cloth widths are preferred. Since the process is a continuous one, the fabric can be of any suitable length but will usually be of normal blanket cloth length prior to being cut into single blankets.

As just indicated the fabric should be composed of at least 10 percent acrylic fibers. The fabric may be a blend of wool, cotton, rayon or like fibers and acrylic fibers. As employed herein, acrylic fiber is defined as a manufactured fiber in which the fiber-forming substance is a long chain synthetic polymer composed of about percent or more by weight of polymerized acrylonitrile units. The fibers are made by usual fiberform ing procedures such as wet-spinning or dry-spinning. While the fabric will ordinarily be constructed from yarns thrown from acrylic staple fibers, continuous acrylic filaments also can be used in the construction of the fabric.

The napped fabric is fed through an ethylene carbonate application zone. In this zone ethylene carbonate is applied to the fabric surface on one or both of the fabric sides. Room temperature is satisfactory, although higher or lower zone temperatures, say 65 to F., can be used, The ethylene carbonate exists in the zone in the form of fine particles, such as in the form of a mist, fog, cloud or the like. Ethylene carbonate is supplied to the zone preferably in solution, with water being a very suitable and preferred solvent. Although ethylene carbonate without being diluted may be applied directly to the mapped fabric, it is more convenient from a material handling standpoint to employ it in solution form so that fine particles can be provided. For best results it has been found that an aqueous solution of from 2.0 to 50 percent by weight (preferably 10 to 30 percent) ethylene carbonate can be employed.

Ethylene carbonate solution can be finely divided by known means. A spray nozzle employing a propelling gas has been found to be quite suitable. In such a spray the particles of ethylene carbonate are suspended in the gas. The particles are directed onto the napped fabric moving longitudinally through the application zone.

The amount of ethylene carbonate picked up by the fabric is quite important. Obviously, a minimum amount will be that required to reduce the shedding and pilling of the fabric as desired. Generally, with greater amounts of ethylene carbonate, shedding and pilling are proportionally reduced. Amounts of ethylene carbonate (not solution) of about 1.0 to 5.0 cubic centimeters per square yard of blanket give good results. However, preferred amounts are in the range of 2.0 to 2.5 cubic centimeters per square yard.

Without undue delay the fabric is continuously fed through a heating zone. The fabric containing the particles of ethylene carbonate solution is heated to evaporate the solution therefrom. Due to the softening action of the ethylene carbonate on the acrylic fibers, crossbonding of the fibers of the nap at the points of fiber intersections is effected. The optimum period of retaining the aliphatic cyclic carbonate will be dependent upon the temperature and the concentration and specific nature of the carbonate, as well as upon other factors. Generally, room temperature is quite satisfactory; however, in general, the temperature of the carbonate solution is between about 50 F. and 250 F.

The temperature of the heating zone is important. The temperature must not reach the degradation point of acrylic fibers which usually is about 350 F. However, dimensional stability of the fabric is affected undesirably above 290 F.; hence, one should employ a treating temperature below this. A temperature of at least about 225 F. will be employed for normal production speed requirements and to insure proper cross-bonding in the fabric.

Next, the treated fabric is cooled, the cooling preferably being rapidly carried out. This can be accomplished by directing a coolant against the treated napped fabric as it moves continuously through a cooling zone. Preferably the fabric is cooled with cool air to below 150 F., the cooling being attained within a few seconds, say 5-10 seconds, after the fabric leaves the heating zone. The thus-treated fabric has greatly enhanced resistance to shedding and pilling.

The drawing comprises a schematic illustration of a method and means for treating the napped fabric in accordance with the present invention.

A napped cloth is withdrawn from a container 11 or other source of supply. As illustrated, the cloth is supplied from a portable container in which the cloth has been plaited. Driven feed roll 12 is provided to withdraw the cloth and to supply same onto scray 13 on which the cloth is forwarded in small folds. After leaving the exit end of the scray, cloth 10 is passed between tension bars 14 and 15 which serve properly to tension the cloth so that it can be better treated in accordance with the invention.

The apparatus in which the cloth is treated with ethylene carbonate generally comprises a vertically elongated structure composed of an ethylene carbonate spray chamber 16, a long heating chamber 17, and a cooling chamber 18. Inside suitably supported frame a bottom idler roll 21 is provided which serves as a guide for directing the cloth upwardly through the apparatus. Mounted on frames 22 and 23 are ethylene carbonate supply headers 24 and 25. A plurality of conduits 26 and 27 extend from these headers to a plurality of spray nozzles 28 and 30. Gas supply headers 31 and 32 and conduits 33 and 34 provide for movement of a propelling gas to the spray nozzles where the solution is finely divided and carried by the propelling gas against the faces of the cloth normally moving therebetween. Obviously, the number of nozzles will depend on the width of the cloth and wideness of the spray of the nozzles. Suspended from frames 22 and 23 are bottom pans 35 and 36 for receiving solution impinged against the cloth but not retained thereon. Above the idler roll 21 and just below the gap between pans 35 and 36 are pipes 37 and 38 having properly positioned apertures therealong, whereby gas under pressure escaping therefrom will provide an updraft or air curtain so that during operation a minimal amount of unretained impinged solution will pass below the pipes. A bottom drip pan 40 is provided at the bottom of the apparatus to retain any solution which may fall to that location. A cowling 41 covers the means used to apply the solution to the fabric. For best application results, tips 42 and 43 of the spray nozzles 28 and 30 are located at a distance of about 5 to 9 inches from the respective faces of the cloth. This produces optimum uniform application of solution to the cloth.

The cloth moves out of the spray chamber 16 into heating chamber 17, wherein the cloth is heated and the solution evaporated therefrom. A suitable chamber is a Heat-Pack unit manufactured by Southern Machine Products, Inc., Charlotte, N.C. Such unit comprises a housing 44 in which there are contained opposed banks of heating elements such as infra-red radiant heaters 45. Other heating means can be employed as long as the solution is removed from the cloth under the process conditions above-outlined. The heaters are arranged to swing away from the cloth automatically in response to stoppage of the cloth movement therebetween. The heaters are swung into drying position as the motion of the cloth through the heating chamber is commenced. Vapors of ethylene carbonate solution flow concurrently with the cloth and are exhausted from the heating chamber through chimney pots 46 and 47.

Next, the cloth moves from the heating chamber into cooling chamber 18. Opposed cool air supply ducts 48 and 50 provide means for quickly cooling the treated cloth. Sufficient cool air is supplied to the cloth to reduce the cloth temperature to a temperature less than F. before it is laterally compressed by top idler roll 51. The quick cooling also serves to minimize stretching of the cloth due to longitudinal tensioning. Air ducts 52 and 53 permit return of the cooling air to a refrigerator, not shown.

Next, the cloth may be taken up in an orderly manner for further processing. This can be accomplished by the use of guide rollers 54 and 55, together with a driven roll 56 and nip-forming idler 57. The cloth falls through plaiter 58 reciprocated by a cam drive means, not shown. The cloth is laid in container 60 in the form of uniform folds or plaits.

In operating the apparatus a napped cloth composed of acrylic fibers is laced and moved through the apparatus as shown in the drawing. Ethylene carbonate solution is atomized by means of spray nozzle tips 42 and 43 and associated apparatus. The solution is impinged against the moving cloth on one or both of its faces. Heaters 45 are energized to evaporate the solution from the cloth. Cool air is moved through the cooling cham ber 18 in order to quickly cool the treated cloth. Thereafter the cloth is taken up in a uniform manner such as being piddled by plaiter 58 into container 60.

The following example is given to illustrate the invention. It is not intended to limit the invention in any manner.

Example A 10 oz. per yard blanket fabric was woven in a count of 29 picks per inch, 5Z turns per inch in the singles and 38 turns per inch in the ply, spun from 3 denier per filament 1 /2 to 3 inch acrylic staple fibers. The fibers were wet spun from an acrylonitrile polymer blend composed of (a) a copolymer of 94 percent acrylonitrile and 6 percent vinyl acetate, and (b) a copolymer of 50 percent acrylonitrile and 50 percent 2-methyl-5-vinylpyridine, said blend containing 6 percent methyl vinylpyridine based on the total weight of the blend. The fabric was noted to have a tendency to pill after a few launderings.

One hundred yards of the fabric were treated in the apparatus described above and shown in the attached drawing. The speed at which the fabric moved through the apparatus was 22 yards per minute. An aqueous solution containing 20 percent ethylene carbonate was prepared. From spray nozzle tips located 7 inches from the faces of the fabric, the solution was atomized and propelled onto the fabric at room temperature. Each square yard of the fabric picked up 2.2 cubic centimeters of ethylene carbonate. In 1.2 seconds after being sprayed with the ethylene carbonate solution the fabric was passed between the banks of heating lamps. The surface of the blanket fabric attained a temperature of 275 F. over a heating period of about 2.5 seconds. Next, the fabric was cooled quickly by directing cool air thereon. Before the fabric reached the top idler roll, the temperature of the fabric had dropped to 125 F. in about 2.4 seconds. The fabric was laundered five times under normal laundering conditions. It was observed that the hand of the fabric remained very soft and the color thereof was not affected. In addition, the fabric exhibited excellent resistance to matting, pilling and shedding.

Similarly excellent results are accomplished with fabrics made from other acrylic fibers, such as those fibers made of a copolymer containing 94 percent acrylonitrile and 6 percent vinyl acetate, or of a copolymer containing 94 percent acrylonitrile and 6 percent methyl acrylate.

There are numerous advantages of the apparatus and method described above. In accordance with the invention napped fabric is rendered highly resistant to pilling without adversely affecting the hand thereof. The method provides a continuous treatment of a napped fabric with ethylene carbonate solution, the fabric being made of acrylic fibers. The apparatus is simple in construction and provides means for continuous treatment of a napped fabric with ethylene carbonate so as to render the fabric resistant to pilling and matting while maintaining a pleasing tactile quality.

It is not intended that the invention be limited solely to the details of the embodiments set forth above. It will be recognized that numerous modifications conforming to the spirit of the invention may be made. Therefore, it is intended that the invention be limited only by the scope of the following claims.

What is claimed is:

1. Apparatus for treating napped fabric composed at least in part of acrylic fibers comprising:

(a) means for feeding said fabric from a source of pp y;

(b) a pair of carbonate supply headers;

(c) a pair of propelling gas supply headers;

(d) conduits extending between said carbonate supply headers and said gas supply headers to a plurality of opposed spray nozzles, the nozzles being disposed so that streams of finely divided carbonate solution suspended in the propelling gas are directed onto the said fabric normally passing therebetween;

(e) opposed banks of heating elements disposed along the fabric path after the fabric has been sprayed for heating both sides of the fabric and to evaporate the carbonate therefrom;

(f) cooling means disposed in the fabric path after the fabric has been heated to reduce the temperature of the fabric quickly;

(g) means for pulling the fabric between said spray nozzles, said heating elements and said cooling means; and

(h) means for taking up the fabric in an orderly manner.

2. Apparatus for treating napped fabric composed at least in part of acrylic fibers comprising:

(a) a frame supporting a pair of carbonate supply headers;

(b) a pair of propelling gas supply headers;

(c) conduits extending between said carbonate supply headers and said gas supply headers to a plurality of opposed spray nozzles, the nozzles being disposed so that streams of finely divided carbonate solution suspended in the propelling gas normally emitted therefrom are directed generally horizontally onto 8 the said fabric normally passing upwardly therebetween;

(d) opposed banks of heating elements disposed along the fabric path above the spray nozzles for heating both sides of the fabric and to evaporate the carbonate therefrom; and

(e) opposed cool air ducts disposed in the fabric path above the heating lamps to reduce the temperature of the fabric quickly by a flow of cool air thereon.

3. Apparatus for treating napped fabric composed at least in part of acrylic fibers comprising:

(a) means for feeding said fabric from a source of pp y;

(b) a frame supporting a pair of carbonate supply headers;

(c) a pair of propelling gas supply headers;

(d) conduits extending between said carbonate supply headers and said gas supply headers to a plurality of opposed spray nozzles, the nozzles being disposed so that streams of finely divided carbonate solution suspended in the propelling gas normally emitted therefrom are directed generally horizontally onto both sides of said fabric normally passing upwardly therebetween;

(e) a pair of opposed banks of heating elements disposed along the fabric path and mounted on the frame above the spray nozzles for heating both sides of the fabric and to evaporate the carbonate therefrom;

(f) a pair of opposed cool air ducts disposed in the fabric path and mounted just above the heating elements to reduce the temperature of the fabric quickly by a flow of cool air thereon;

(g) a first idler roll mounted below said nozzles and a second idler roll mounted above said cool air ducts for guiding the fabric upwardly between said spray nozzles, said heating elements and said ducts;

(h) driven means for forwarding said fabric upwardly between said spray nozzles, said heating lamps, and said ducts; and

(i) means for taking up the fabric in an orderly manner.

4. Apparatus for treating napped fabric composed at least in part of acrylic fibers comprising:

(a) a driven roll for feeding said fabric from a source of supply;

(b) a frame supporting a pair of carbonate supply headers;

(c) a pair of propelling gas supply headers;

(d) conduits extending between said carbonate supply headers and said gas supply headers to a plurality of opposed spray nozzles, the nozzles being disposed so that streams of finely divided carbonate solution suspended in the propelling gas normally emitted therefrom are directed generally horizontally onto both sides of said fabric normally passing upwardly therebetween;

(e) a pair of opposed banks of heating elements disposed along the fabric path and mounted in a housing on the frame above the spray nozzles for heating both sides of the fabric and to evaporate the carbonate therefrom;

(f) a pair of opposed cool air supply ducts disposed in the fabric path and mounted just above the heating elements adapted to reduce the temperature of the fabric quickly by a flow of cool air thereon;

(g) a pair of chimney pots mounted between said heating elements and said cool air ducts for exhausting the evaporated carbonate;

(h) a pair of cool air return ducts mounted above the cool air supply ducts;

(i) a first idler roll mounted below said nozzles and a second idler roll mounted above said cool air supply ducts for guiding the fabric upwardly between said spray nozzles, said heating elements and said cool air supply ducts;

(j) a driven roll for forwarding said fabric upwardly between said spray nozzles, said heating elements and said cool air supply ducts; and

(k) a fabric plaiter for depositing the treated fabric in a container in the form of folds.

5. Apparatus for treating napped fabric composed at least in part of acrylic fibers comprising: I

(a) a driven roll for feeding said fabric from a source of supply onto a scray;

(b) a frame supporting a pair of carbonate supply headers;

(c) a pair of propelling gas supply headers;

(d) conduits extending between said carbonate supply headers and said gas supply headers to a plurality of opposed spray nozzles, the nozzles being disposed so that streams of finely divided carbonate solution suspended in the propelling gas normally emitted therefrom are directed generally horizontally onto both sides of said fabric normally passing upwardly therebetween;

(e) a pair of drip pans mounted on said frame below said nozzles providing a fabric passageway therebetween and adapted to receive carbonate emitted from said nozzles but not retained on the surfaces of said fabric;

(f) a pair of pipes positioned below and adjacent the fabric passageway provided by the drip pans, said pipes being provided with apertures, whereby gas under pressure escaping therefrom will provide an updraft through said passageway;

(g) a pair of opposed banks of heating lamps disposed along the fabric path and mounted in a housing on the frame above the spray nozzles for heating both sides of the fabric and to evaporate the carbonate therefrom;

(h) a pair of opposed cool air supply ducts disposed in the fabric path and mounted just above the heating 8, lamps adapted to reduce the temperature of the fabric quickly by a flow of cool air thereon;

(i) a pair of chimney pots mounted between said heating lamps and said cool air ducts for exhausting the evaporated carbonate;

(j) a pair of cool air return ducts mounted above the cool air supply ducts;

(k) a first idler roll mounted below said nozzles and a second idler roll mounted above said cool air supply ducts for guiding the fabric upwardly between said spray nozzles, said heating lamps and said cool air supply ducts;

(l) a driven delivery roll having an associated nip-forming idler roll for forwarding said fabric upwardly between said spray nozzles, said heating lamps and said cool air supply ducts;

(m) a tension bar in the fabric path between the exit end of said scray and said first idler roll for maintaining a predetermined tension in the fabric; and

(n) a fabric plaiter adapted to receive the fabric from said driven delivery roll and to deposit the treated fabric into a container in the form of folds.

References Cited by the Examiner UNITED STATES PATENTS 273,013 2/1883 Bedford. 2,136,957 11/1938 Sendzimir 118-67 X 2,532,471 12/ 1950 Speers 68-5 2,897,042 7/ 1959 Heiks 8-130.1 2,938,811 5/1960 Hermes 8-1301 2,973,635 3/1961 Speers 68-5 2,987,796 6/ 1961 Evans et a1. 28-1 2,997,772 8/1961 Etchison 28-1 IRVING BUNEVICH, Primary Examiner.

R. R. MACKEY, Examiner. 

2. APPARATUS FOR TREATING NAPPED FABRIC COMPOSED AT LEAST IN PART OF ACRYLIC FIBERS COMPRISING: (A) A FRAME SUPPORTING A PAIR OF CARBONATE SUPPLY HEADERS; (B) A PAIR OF PROPELLING GAS SUPPLY HEADERS; (C) CONDUITS EXTENDING BETWEEN SAID CARBONATE SUPPLY HEADERS AND SAID GAS SUPPLY HEADERS TO A PLURALITY OF OPPOSED SPRAY NOZZLES, THE NOZZLES BEING DISPOSED SO THAT STREAMS OF FINELY DIVIDED CARBONATE SOLUTION SUSPENDED IN THE PROPELLING GAS NORMALLY EMITTED THEREFROM ARE DIRECTED GENERALLY HORIZONTALLY ONTO THE SAID FABRIC NORMALLY PASSING UPWARDLY THEREBETWEEN; 